#!/bin/bash

# 初始化a b 变量的值

# + - *  /  % 
a=10
b=20

c=`expr $a + $b`
d=`expr $a - $b`
d1=`expr $a \* $b`
d3=`expr $a / $b`
d2=`expr $a % $b`

echo  "$a + $b = $c"
echo  "$a - $b = $d"
echo  "$a * $b = $d1"
echo  "$a / $b = $d3"
echo  "$a % $b = $d2"

echo  " $a == $b"





# echo  "$a - $b"
# echo  "$a \* $b"
# echo  "$a % $b"


